Charter schools will have “new chances to grow” in Mayor de Blasio’s administration — including more co-locations with traditional public schools, he said Monday.

Launching the second day of a charm offensive to defuse the war he launched against charters, the mayor praised the alternative schools for providing a model for the rest of the system.

“They’re doing good work in many ways for kids,” de Blasio said on WNYC radio.

“That innovative element though has to be brought over to the mainstream of traditional public schools because that’s where the vast majority of the kids are. And we can do that.”

The mayor suddenly began talking up charters Sunday (inset) — just as Albany was negotiating the $142 billion state budget, which he’s hoping will provide the city with up to $540 million a year to expand pre-kindergarten classes.

To get that money, de Blasio needs the support of Gov. Cuomo, who has pledged to come to the aid of charters that get blocked by the mayor.

Now that he and Cuomo are closer on charters, de Blasio predicted he would get a “solid result” out of Albany on pre-K funding.

The mayor said once he straightens out the faulty “co-location” process inherited from his predecessor, he would allow more charters to locate within public buildings.

“Once we get the co-location process right, there’s going to be an opportunity for charters to continue to have new chances to grow,” the mayor said.

He even expressed admiration for the longer school day that is common in charter classes, which generally aren’t constrained by union rules.

“If we give kids more time in the classroom setting, than we can achieve better results,” the mayor said.

But he didn’t say if he would retract his proposal to charge rent to the wealthier charters or restore $210 million in capital funds he shifted from the schools earlier this year.

The mayor’s second day of a kinder and gentler approach to charters comes as he’s getting pummeled in polls and in $3.6 million in TV ads bought by charter advocates.

Board of Regents Chancellor Merryl Tisch, a strong charter supporter, said the mayor is looking for common ground.

“He made a rookie mistake. Let’s help him move forward,” she said.

But charter school insiders said de Blasio’s conciliatory p.r. gesture, while welcome, is style over substance.